day 2

lib.h

@@ -0,0 +1,147 @@
+#pragma once
+#include <stdlib.h>
+#include <stdcountof.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <string.h>
+
+#define xstr(s) str(s)
+#define str(s) #s
+
+typedef uint64_t bcdint;
+
+static
+void printns(size_t len, unsigned char chars[len]) {
+    syscall(SYS_write, STDOUT_FILENO, chars, len);
+}
+
+static 
+void printptr(uintptr_t v) {
+    char buf[sizeof(uintptr_t)*2] = { };
+    char *p = buf+countof(buf);
+    for (size_t i = 0; i < countof(buf); i++) {
+        p--;
+        if ((v & 0x0F) < 0xA) {
+            *p = '0' + (v & 0x0F);
+        } else {
+            *p = 'A' - 0xA + (v & 0x0F);
+        }
+        v >>= 4;
+    }
+    syscall(SYS_write, STDOUT_FILENO, p, countof(buf));
+}
+
+static
+void print_many_char(size_t len, char chars[len]) {
+    syscall(SYS_write, STDOUT_FILENO, chars, len);
+}
+
+#define print(string) print_many_char(sizeof(string)-1, string)
+
+static
+void printd(unsigned long v) {
+    if (!v) {
+        print("0");
+        return;
+    }
+    char buf[32];
+    char *p = buf+32;
+    unsigned count = 0;
+    while (v) {
+        p--;
+        *p = '0' + (v % 10);
+        v /= 10;
+        count++;
+    }
+    syscall(SYS_write, STDOUT_FILENO, p, count);
+}
+
+static
+void printh(unsigned long v) {
+    if (!v) {
+        print("0");
+        return;
+    }
+    char buf[32];
+    char *p = buf+32;
+    unsigned count = 0;
+    while (v) {
+        p--;
+        if ((v & 0x0F) < 0xA) {
+            *p = '0' + (v & 0x0F);
+        } else {
+            *p = 'A' - 0xA + (v & 0x0F);
+        }
+        v >>= 4;
+        count++;
+    }
+    syscall(SYS_write, STDOUT_FILENO, p, count);
+}
+
+static
+void print_hex_char(unsigned char v) {
+    char buf[2];
+
+    if ((v >> 4) < 0x0A) {
+        buf[0] = '0' + (v >> 4);
+    } else {
+        buf[0] = 'A' - 0xA + (v >> 4);
+    }
+
+    if ((v & 0x0F) < 0xA) {
+        buf[1] = '0' + (v & 0x0F);
+    } else {
+        buf[1] = 'A' - 0xA + (v & 0x0F);
+    }
+
+    syscall(SYS_write, STDOUT_FILENO, buf, sizeof(buf));
+}
+
+static
+void print_pre_hex(size_t len, unsigned char prefix[len], unsigned long v) {
+    printns(len, prefix);
+    printh(v);
+}
+
+static
+void print_pre_ptr(size_t len, unsigned char prefix[len], void *ptr) {
+    printns(len, prefix);
+    printptr((uintptr_t)ptr);
+}
+
+#define print_watch_ptr(expr) print_pre_ptr(\
+        sizeof(#expr ": ")-1, (unsigned char*)(#expr ": "), expr)
+#define print_watch_hex(expr) print_pre_hex(\
+        sizeof(#expr ": ")-1, (unsigned char*)(#expr ": "), expr)
+
+static
+bcdint grabbcd(unsigned char *s, unsigned char **end) {
+    bcdint r = 0;
+    for (; *s >= '0' && *s <= '9'; s++)
+        r = (r << 4) + (*s - '0');
+    if (end) *end = s;
+    return r;
+}
+
+static
+unsigned grabnum(const char *s, const char **end) {
+    unsigned r = 0;
+    for (; *s >= '0' && *s <= '9'; s++)
+        r = r * 10 + (*s - '0');
+    *end = s;
+    return r;
+}
+
+// from wikipedia, the free encyclopedia
+// https://en.wikipedia.org/wiki/Binary-coded_decimal
+static bcdint bcdadd(bcdint a, bcdint b) {
+    bcdint t1, t2;
+    t1 = a + 0x0666666666666666;
+    t2 = t1 ^ b;
+    t1 = t1 + b;
+    t2 = t1 ^ t2;
+    t2 = ~t2 & 0x1111111111111110;
+    t2 = (t2 >> 2) | (t2 >> 3);
+    return t1 - t2;
+}